atoms vocab Flashcards
atomic theory
all matter is made up of indivisible particles called atoms
negatively charged particles orbiting the nucleus
electrons
particles with no charge in the nucleus - neutral
neutrons
tells you how many protons are in an atom of the element
atomic number
amount of particles equal to 1 mole
avagadros number
electrons in the outermost level of an atom
valence electrons
Greek philosopher who suggested the universe is made of indivisible units called atoms
democritus
British scientist proposed that most of the mass of the
atom was concentrated in the atom’s center - discovered nucleus;
rutherford
a chemical
compound always contains the same
elements in exactly the same proportions by
weight or mass
law of definite proportions
positively charged dense core located in center of atom
nucleus
a charged particle
ion
area where electrons can be found in the atom
energy level
lowest state of energy of an atom
ground state
revised the Atomic Theory in 1808; based his theory
on experimental evidence; considered to be the foundations for the modern atomic theory.
dalton
danish physicist; suggested that the energy of each electron
was related to the path it follows around the
nucleus.
bohr
smallest part of a substance that cant be broken down chemically
atom
positively charged particle in nucleus
proton
equals total # of subatomic particles in nucleus
mass #
unit used to count particles
mole
a particle of light
photon
electrons move to this when it gains energy
excited state
British scientist who suggested atoms were not indivisible; discovered electrons
thomson
elements that vary in mass #’s bc their # of neutrons differ
isotope
what are the three characteristics of atoms
- each element has a unique # of protons
- neutral atoms have no overall charge
- positive+negative charges attract each other inside the atom
what did Bohr contribute to atomic theory
he said that energy of each electron was related to the path it follows around the nucleus (said electrons behave more like waves)
most likely place to find an electron
orbital or levels
what places are electrons never found
nucleus and in between levels
how to identify an isotope
if mass # in periodic table doesn’t = mass # given (calculated)
how to identify an ion
protons don’t = electrons
how to identify a neutral atom
mass # in periodic table = mass # given/calculated AND protons = electrons
